<html>
<head><meta charset="utf-8"><title>2020-10-29 meeting agenda · t-compiler/wg-prioritization · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/index.html">t-compiler/wg-prioritization</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html">2020-10-29 meeting agenda</a></h3>

<hr>

<base href="https://rust-lang.zulipchat.com">

<head><link href="https://rust-lang.github.io/zulip_archive/style.css" rel="stylesheet"></head>

<a name="214201587"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214201587" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214201587">(Oct 22 2020 at 15:13)</a>:</h4>
<p>Just created next week's agenda <a href="https://hackmd.io/DEgK3x4SRJCQlqV0McB0xw?both">https://hackmd.io/DEgK3x4SRJCQlqV0McB0xw?both</a></p>



<a name="214201626"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214201626" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214201626">(Oct 22 2020 at 15:13)</a>:</h4>
<p><span class="user-mention" data-user-id="250987">@apiraino</span> I've just filled with the corresponding wg but as we've already talked it seems like there's a bug in the <a href="https://rust-lang.github.io/compiler-team/about/triage-meeting/">compiler-team website</a></p>



<a name="214201751"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214201751" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214201751">(Oct 22 2020 at 15:14)</a>:</h4>
<p>if you check it now, it will say <code>This Week: 2020-10-22 - 2020-10-29: Meta and MIR Optimizations</code></p>



<a name="214201815"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214201815" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214201815">(Oct 22 2020 at 15:15)</a>:</h4>
<p>but as we've seen this will change on 28 instead of 29</p>



<a name="214201880"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214201880" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214201880">(Oct 22 2020 at 15:16)</a>:</h4>
<p>there's an off by one in the JavaScript there, if someone wants to fix that would be great :)</p>



<a name="214201944"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214201944" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> apiraino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214201944">(Oct 22 2020 at 15:16)</a>:</h4>
<p>right. I'll have a look, I think</p>



<a name="214202027"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214202027" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> apiraino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214202027">(Oct 22 2020 at 15:16)</a>:</h4>
<p>one thing I don't understand is why the "week" starts on <del>Wed</del> Thu. Is that because today is the day 0 because of the meeting?</p>



<a name="214202147"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214202147" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214202147">(Oct 22 2020 at 15:17)</a>:</h4>
<p>right</p>



<a name="214202177"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214202177" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214202177">(Oct 22 2020 at 15:18)</a>:</h4>
<p>maybe we can change this week with this iteration</p>



<a name="214202214"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214202214" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214202214">(Oct 22 2020 at 15:18)</a>:</h4>
<p>or something</p>



<a name="214202279"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214202279" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214202279">(Oct 22 2020 at 15:18)</a>:</h4>
<p>btw I've executed also all the follows up <a href="https://forge.rust-lang.org/compiler/prioritization/procedure.html#follow-ups-from-previous-meeting">https://forge.rust-lang.org/compiler/prioritization/procedure.html#follow-ups-from-previous-meeting</a></p>



<a name="214854715"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214854715" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> apiraino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214854715">(Oct 28 2020 at 15:42)</a>:</h4>
<p>I've added some content to the agenda, checked the issues and added some summaries. <span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> I've tried adding some context to the beta nominations like <span class="user-mention silent" data-user-id="116083">pnkfelix</span> mentioned <a href="#narrow/stream/238009-t-compiler.2Fmeetings/topic/Suggestions.20to.20improve.20the.20weekly.20meeting.20agenda.3F/near/214189113">last week</a>.</p>



<a name="214867118"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214867118" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214867118">(Oct 28 2020 at 17:03)</a>:</h4>
<p><span class="user-mention silent" data-user-id="250987">apiraino</span> <a href="#narrow/stream/227806-t-compiler.2Fwg-prioritization/topic/2020-10-29.20meeting.20agenda/near/214854715">said</a>:</p>
<blockquote>
<p>I've added some content to the agenda, checked the issues and added some summaries. <span class="user-mention silent" data-user-id="116266">Santiago Pastorino</span> I've tried adding some context to the beta nominations like <span class="user-mention silent" data-user-id="116083">pnkfelix</span> mentioned <a href="#narrow/stream/238009-t-compiler.2Fmeetings/topic/Suggestions.20to.20improve.20the.20weekly.20meeting.20agenda.3F/near/214189113">last week</a>.</p>
</blockquote>
<p>cool, I'm going to go over things in a bit</p>



<a name="214887785"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214887785" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214887785">(Oct 28 2020 at 19:42)</a>:</h4>
<p>about ...</p>



<a name="214887787"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214887787" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214887787">(Oct 28 2020 at 19:42)</a>:</h4>
<ul>
<li>"Fix <a href="https://github.com/rust-lang/rust/issues/78192">#78192</a>" <a href="https://github.com/rust-lang/rust/pull/78247">rust#78247</a></li>
</ul>



<a name="214887821"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214887821" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214887821">(Oct 28 2020 at 19:43)</a>:</h4>
<p>we've already backported a disable the opt patch, right?</p>



<a name="214887838"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214887838" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214887838">(Oct 28 2020 at 19:43)</a>:</h4>
<p>in that case, why would we want to backport that?</p>



<a name="214887876"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214887876" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214887876">(Oct 28 2020 at 19:43)</a>:</h4>
<p>I meant, it is nominated so it's up for discussion but I'm trying to understand to properly summarize for the agenda</p>



<a name="214887931"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214887931" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214887931">(Oct 28 2020 at 19:44)</a>:</h4>
<p>the current summarization we have is</p>



<a name="214887932"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214887932" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214887932">(Oct 28 2020 at 19:44)</a>:</h4>
<ul>
<li>"Fix <a href="https://github.com/rust-lang/rust/issues/78192">#78192</a>" <a href="https://github.com/rust-lang/rust/pull/78247">rust#78247</a><ul>
<li>opened by <code>simonvandel</code></li>
<li>assigned  <span class="user-mention" data-user-id="124288">@oli</span> and r+</li>
<li>on 1.49.0-nightly</li>
<li>fixes <a href="https://github.com/rust-lang/rust/issues/78192">rust#78192</a> (unsoudnness on MIR optimization InstCombine that introduces an incorrect use of a local after its storage has ended)</li>
<li><span class="user-mention" data-user-id="124288">@oli</span> raises the issue to merge this optimization without backtracking, PR author mentions being the way</li>
</ul>
</li>
</ul>



<a name="214887961"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214887961" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214887961">(Oct 28 2020 at 19:44)</a>:</h4>
<p>but doesn't seem exactly right to me</p>



<a name="214888302"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214888302" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214888302">(Oct 28 2020 at 19:47)</a>:</h4>
<p>actually, we enabled the optimization again in nightly ... so ... this should just land in nightly?</p>



<a name="214888316"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214888316" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214888316">(Oct 28 2020 at 19:47)</a>:</h4>
<p>cc <span class="user-mention" data-user-id="255061">@LeSeulArtichaut</span> <span class="user-mention" data-user-id="211727">@Jonas Schievink</span></p>



<a name="214888396"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214888396" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214888396">(Oct 28 2020 at 19:48)</a>:</h4>
<p>to make a more concrete question, is <a href="https://github.com/rust-lang/rust/issues/78247">#78247</a> beta nomination correct? it doesn't seem like that to me</p>



<a name="214888447"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214888447" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214888447">(Oct 28 2020 at 19:49)</a>:</h4>
<p>I think it is correct, but maybe not warranted</p>



<a name="214888487"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214888487" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jonas Schievink  [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214888487">(Oct 28 2020 at 19:49)</a>:</h4>
<p>That should <em>not</em> be backported as it would reintroduce the unsound optimization</p>



<a name="214888528"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214888528" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214888528">(Oct 28 2020 at 19:49)</a>:</h4>
<p>Oh</p>



<a name="214888597"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214888597" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jonas Schievink  [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214888597">(Oct 28 2020 at 19:50)</a>:</h4>
<p>But the disable patch wasn't backported, right?</p>



<a name="214888614"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214888614" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jonas Schievink  [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214888614">(Oct 28 2020 at 19:50)</a>:</h4>
<p>Because beta still miscompiles this example:</p>
<div class="codehilite" data-code-language="Rust"><pre><span></span><code><span class="k">fn</span> <span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="kd">let</span><span class="w"> </span><span class="n">a</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="k">u32</span><span class="p">;</span><span class="w"></span>
<span class="w">    </span><span class="kd">let</span><span class="w"> </span><span class="n">b</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">2</span><span class="k">u32</span><span class="p">;</span><span class="w"></span>

<span class="w">    </span><span class="kd">let</span><span class="w"> </span><span class="k">mut</span><span class="w"> </span><span class="n">c</span>: <span class="o">*</span><span class="k">const</span><span class="w"> </span><span class="kt">u32</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="o">&amp;</span><span class="n">a</span><span class="p">;</span><span class="w"></span>
<span class="w">    </span><span class="kd">let</span><span class="w"> </span><span class="n">d</span>: <span class="kp">&amp;</span><span class="kt">u32</span> <span class="o">=</span><span class="w"> </span><span class="o">&amp;</span><span class="n">b</span><span class="p">;</span><span class="w"></span>

<span class="w">    </span><span class="kd">let</span><span class="w"> </span><span class="n">x</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">unsafe</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="o">&amp;*</span><span class="n">c</span><span class="w"> </span><span class="p">};</span><span class="w"></span>
<span class="w">    </span><span class="n">c</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">d</span><span class="p">;</span><span class="w"></span>
<span class="w">    </span><span class="kd">let</span><span class="w"> </span><span class="n">z</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="o">*</span><span class="n">x</span><span class="p">;</span><span class="w"></span>

<span class="w">    </span><span class="n">assert_eq</span><span class="o">!</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="n">z</span><span class="p">);</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>
</code></pre></div>



<a name="214888623"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214888623" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214888623">(Oct 28 2020 at 19:50)</a>:</h4>
<p>I think it was accepted last week</p>



<a name="214888648"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214888648" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214888648">(Oct 28 2020 at 19:50)</a>:</h4>
<p>Maybe it hasn’t been backported yet</p>



<a name="214888651"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214888651" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jonas Schievink  [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214888651">(Oct 28 2020 at 19:50)</a>:</h4>
<p>That's <a href="https://github.com/rust-lang/rust/pull/78195">https://github.com/rust-lang/rust/pull/78195</a></p>



<a name="214888659"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214888659" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jonas Schievink  [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214888659">(Oct 28 2020 at 19:50)</a>:</h4>
<p>Yeah, hasn't been backported yet</p>



<a name="214888685"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214888685" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214888685">(Oct 28 2020 at 19:51)</a>:</h4>
<p>so let's remove beta nomination then?</p>



<a name="214888714"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214888714" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214888714">(Oct 28 2020 at 19:51)</a>:</h4>
<p><span class="user-mention" data-user-id="211727">@Jonas Schievink</span> given that you have a bit more context, can you do so and explain briefly?</p>



<a name="214888720"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214888720" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214888720">(Oct 28 2020 at 19:51)</a>:</h4>
<p>(deleted)</p>



<a name="214888733"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214888733" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214888733">(Oct 28 2020 at 19:51)</a>:</h4>
<p>it seemed very weird to me</p>



<a name="214888906"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214888906" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jonas Schievink  [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214888906">(Oct 28 2020 at 19:53)</a>:</h4>
<p>The optimization was unsound and made it to beta, then it got disabled in <a href="https://github.com/rust-lang/rust/issues/78195">#78195</a>, then <a href="https://github.com/rust-lang/rust/issues/78247">#78247</a> incorrectly fixed it and reenabled it, so I opened <a href="https://github.com/rust-lang/rust/issues/78434">#78434</a> to disable it again.</p>



<a name="214888971"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214888971" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jonas Schievink  [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214888971">(Oct 28 2020 at 19:53)</a>:</h4>
<p><a href="https://github.com/rust-lang/rust/issues/78195">#78195</a> and <a href="https://github.com/rust-lang/rust/issues/78434">#78434</a> are basically the same PR/diff</p>



<a name="214888977"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214888977" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214888977">(Oct 28 2020 at 19:53)</a>:</h4>
<p><span class="user-mention" data-user-id="211727">@Jonas Schievink</span> IIRC anyone can file a PR to backport? I could file one if it helps</p>



<a name="214888993"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214888993" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jonas Schievink  [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214888993">(Oct 28 2020 at 19:53)</a>:</h4>
<p>So if we just backport <a href="https://github.com/rust-lang/rust/issues/78195">#78195</a> that would fix beta</p>



<a name="214889065"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214889065" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jonas Schievink  [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214889065">(Oct 28 2020 at 19:54)</a>:</h4>
<p>I was going to wait until the next batch of backports is approved, but I don't really mind</p>



<a name="214889118"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214889118" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jonas Schievink  [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214889118">(Oct 28 2020 at 19:54)</a>:</h4>
<p>Feel free to file one though</p>



<a name="214889151"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214889151" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214889151">(Oct 28 2020 at 19:54)</a>:</h4>
<p>So wait until next T-compiler meeting?</p>



<a name="214889172"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214889172" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jonas Schievink  [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214889172">(Oct 28 2020 at 19:55)</a>:</h4>
<p>Actually it might be better to coordinate backports with T-release, since we usually do them in batches</p>



<a name="214889382"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214889382" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214889382">(Oct 28 2020 at 19:56)</a>:</h4>
<p><span class="user-mention silent" data-user-id="211727">Jonas Schievink</span> <a href="#narrow/stream/227806-t-compiler.2Fwg-prioritization/topic/2020-10-29.20meeting.20agenda/near/214888993">said</a>:</p>
<blockquote>
<p>So if we just backport <a href="https://github.com/rust-lang/rust/issues/78195">#78195</a> that would fix beta</p>
</blockquote>
<p>ok, but that one is already beta accepted so release team will backport it at some point</p>



<a name="214889401"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214889401" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jonas Schievink  [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214889401">(Oct 28 2020 at 19:56)</a>:</h4>
<p>yeah</p>



<a name="214889424"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214889424" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jonas Schievink  [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214889424">(Oct 28 2020 at 19:57)</a>:</h4>
<p>So, no, nothing to discuss by T-compiler to get this fixed</p>



<a name="214889454"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214889454" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214889454">(Oct 28 2020 at 19:57)</a>:</h4>
<p><span class="user-mention silent" data-user-id="116266">Santiago Pastorino</span> <a href="#narrow/stream/227806-t-compiler.2Fwg-prioritization/topic/2020-10-29.20meeting.20agenda/near/214888714">said</a>:</p>
<blockquote>
<p><span class="user-mention silent" data-user-id="211727">Jonas Schievink</span> given that you have a bit more context, can you do so and explain briefly?</p>
</blockquote>
<p>can you do so on github and remove beta nomination or do you want me to do so?</p>



<a name="214889497"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214889497" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214889497">(Oct 28 2020 at 19:57)</a>:</h4>
<p>I wanted to leave that up to you given you seem more involved on the issue but I can also do it :)</p>



<a name="214889693"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214889693" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jonas Schievink  [he/him] <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214889693">(Oct 28 2020 at 19:59)</a>:</h4>
<p>Will do</p>



<a name="214951284"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214951284" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> apiraino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214951284">(Oct 29 2020 at 10:55)</a>:</h4>
<p><span class="user-mention" data-user-id="116266">@Santiago Pastorino</span> added small updates to the agenda (see diff)<br>
(slightly related: the history view of previous versions of the hackmd file looks now broken on my browsers <span aria-label="thinking" class="emoji emoji-1f914" role="img" title="thinking">:thinking:</span>  , tested with firefox 83, chromium)</p>



<a name="214957917"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214957917" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214957917">(Oct 29 2020 at 12:14)</a>:</h4>
<p>you see half the screen of the diff?</p>



<a name="214957921"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214957921" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214957921">(Oct 29 2020 at 12:14)</a>:</h4>
<p>if so, the same happens to me</p>



<a name="214957934"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214957934" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214957934">(Oct 29 2020 at 12:15)</a>:</h4>
<p><span aria-label="+1" class="emoji emoji-1f44d" role="img" title="+1">:+1:</span> to your changed btw</p>



<a name="214964501"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214964501" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> apiraino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214964501">(Oct 29 2020 at 13:18)</a>:</h4>
<p>(deleted)</p>



<a name="214964518"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214964518" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> apiraino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214964518">(Oct 29 2020 at 13:18)</a>:</h4>
<p><span class="user-mention silent" data-user-id="116266">Santiago Pastorino</span> <a href="#narrow/stream/227806-t-compiler.2Fwg-prioritization/topic/2020-10-29.20meeting.20agenda/near/214957917">said</a>:</p>
<blockquote>
<p>you see half the screen of the diff?</p>
</blockquote>
<p>yes :(</p>



<a name="214966170"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29%20meeting%20agenda/near/214966170" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Santiago Pastorino <a href="https://rust-lang.github.io/zulip_archive/stream/227806-t-compiler/wg-prioritization/topic/2020-10-29.20meeting.20agenda.html#214966170">(Oct 29 2020 at 13:32)</a>:</h4>
<p>it should be a hackmd issue then, because the same happens to me</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
</html>